<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="index.css">
</head>

<body>
    <div class="container">
        <canvas id="select" width="400" height="400"></canvas>
        <canvas id="gray" width="400" height="400"></canvas>
        <canvas id="show" width="400" height="400"></canvas>
    </div>
    <div>
        选择文件：<input type="file" name="file" />
        <button>单步</button>
    </div>
    <script src="index.js"></script>
</body>

</html>